Typically endoscopes that may be articulated are limited to single channel optical or electronic image transmission means.
Optical endoscopes that are flexible currently rely upon coherent optical fiber bundles to transmit coarsely pixilated images, giving the user the impression of viewing a scene through a grid, not unlike viewing a scene through a window screen.
Electronic endoscopes (also known as “chip-on-tip” or “chip-on-stick” endoscopes) that are flexible feature a single, highly miniaturized image sensor disposed at the distal end of the device.
Both types of endoscopes (i.e., optical and electronic) typically include fiber optic illumination means for illuminating the operative field which is being directly visualized.
Due to challenges in adequately sealing flexible and articulating endoscopes, these types of devices are limited to cold sterilization techniques. Typically such flexible and articulating endoscopes are hand-held and steered directly by the user.
Stereoscopic (i.e., 3D) endoscopes differ from their non-stereo counterparts in that they are more sensitive to optical misalignments. Not only must each channel be optically aligned for the best image, but also key optical parameters for each channel (such as magnification, bore-sight, image rotation, image focus, etc.) must be identical between the two channels—otherwise, an unwanted parallax will be created in the system, causing depth distortions and user eye strain/fatigue in converging the two images.